1. Field of the Invention
The invention relates to a cooker with at least one electric hotplate and a mounting or trim plate receiving the same, and in particular to such a device wherein means are provided to fix the hotplate against rotation.
2. Prior Art
Cookers with an electric hotplate in a mounting or trim plate are known from DE-OS No. 29 33 296. Locking is brought about by a pin riveted into a retaining clip and engaging in a sleeve shaped or inserted into the bottom cover plate of the hotplate.
Another locking means construction is formed by a downwardly bendable sheet metal part, which is fixed by the central bolt of the electric hotplate. Locking the hotplate is important for the precise positioning of the connections, although the plate is generally circular on the top of the cooker.
An object of the present invention, in connection with a cooker, is to provide good connections, particularly further simplifying a rotation prevention means, so that the fixing of the rotation direction can take place particularly reliably and with limited manufacturing and assembly costs. According to the invention this object is achieved.
The rotation prevention means of the invention is not only a largely rigid member, which must be precisely passed into the depression provided for it, but also a vertically elastically movable tongue, which snaps into a corresponding border depression. The depression is already provided in the hotplates, so that an automatic alignment can be brought about during assembly. Due to the fact that the depression is located in the outer border region, an adequate locking is obtained with minimum forces exerted on the rotation prevention means. Moreover, in the preferred construction, in which the depression is provided in the cover plate of the hotplate, which in turn engages in a depression on the cast border of the electric hotplate, not only the cover plate, but also the cast body is positively rotationally secured. In embodiments in which the cover plate does not rest on the outer cast border of the hotplate body, the rotation prevention means could engage directly in a corresponding depression in the border or rim. The border depression preferably consists of a notch or indentation in the border and which consequently passes through the border at this point.
The rotation prevention means can still be simply kept effective if the hotplate is loose with respect to the mounting plate in that at least one special rotation prevention means is provided, which so interconnects at least two hotplates, that in the case of a rotary movement at least one of said two hotplates would be deformed, without it being necessary to have a direct connection of the rotation prevention means to the mounting plate or without such rotational forces being introduced into the mounting plate. As a result of the rotation prevention means, at least two hotplates can be combined to form a positively secured rotation prevention union, in which the hotplate bodies engaging in the rotation prevention means by means of the latter are reciprocally prevented from rotating, except for a small clearance. Thus, this indirectly leads to a positive locking of the hotplates with respect to the mounting plate.
As a function of the cooker construction at least two, three, more or all the electric hotplates can be drawn downwards with a common, plate-like retaining member in such a way that they are braced against the rims of the reception openings of the mounting plate and are consequently fixed in their vertical position, whereby the retaining member can engage on the central bolt or the central attachments of the hotplate body. Even if said retaining member or its fastening to the central bolt of the hotplate body loosens, the rotation prevention means of the invention is still effective. Nevertheless the retaining member can be incorporated advantageously into the rotation prevention means to the extent that it loads the latter upwards in its engagement position. If said loading is resilient, e.g. due to internal deformation of the sheet metal retaining member or the rotation preventing means, the positive rotation prevention is still retained if the retaining member loosens over a relatively long distance.
However, it is also conceivable to lock the rotation prevention means additionally and directly with respect to the mounting plate, e.g. in that on the bottom of the mounting plate is fixed a support element, e.g. by spot welding and said element fixes the rotation prevention means at least in its vertical position.
The rotation prevention means can engage in the particular hotplate only at a single point, which is appropriately outside the central axis thereof, or at two or more spaced points in retaining manner and they are then all spaced from the central axis or eccentric with respect to the hotplate rotation axis. The arrangement can be made such that the retaining forces are introduced into the rotation prevention means essentially only as thrust or tensile forces.
For the engagement of the rotation means, it is possible to provide on the particular hotplate openings, break-throughs, depressions, projections, lugs, bolts, etc., which are e.g. directly fitted to the cast iron hotplate body and/or to a part fixed thereto, e.g. to a lower, sheet metal end plate of the hotplate body.
Engagement can take place in simple manner by plug-in assembly, the plugging direction being appropriately approximately parallel to the central or rotation axis of the hotplate and directed against its bottom.
Other than in the case of a retaining frame for the heater of a glass ceramic hotplate, the inventive rotation prevention means of the invention does not have to fix the position and spacings of the central axes of the electric hotplates, because they are precisely defined by the reception openings of the mounting plate and to this extent the mounting plate fulfils the function of such a retaining frame. Thus, the rotation prevention means can be formed by individual rods connected to the hotplates in the manner of blocked or closed cranks, but can also be formed by a single plate or frame-like component with projections.